An optical unit 10 includes: a plurality of lenses L1-L4 that form an object image on an image plane that is a light-receiving surface of a CCD 33 an aperture diaphragm B1 and an infrared absorption filter F disposed on the image plane side relative to the aperture diaphragm B1, the infrared absorption filter including coating surfaces resulting from a YAG laser cut-off film FA and an LD laser cut-off film FB that each cut off predetermined laser light being formed respectively, and an F number FNO, a maximum image height IH, and a distance Δd between a paraxial image formation position in a ghost optical path on which a light beam emitted from the aperture diaphragm BI is reflected by the image plane and further reflected by the coating surface and reaches the image plane again and the image plane satisfy (Expression 1):
